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1.
烯啶虫胺的水解与光解行为研究   总被引:1,自引:0,他引:1  
张传琪  胡静  王鸣华 《生态环境》2011,20(11):1735-1738
通过室内模拟实验研究了烯啶虫胺在不同pH值和温度下的水解动态及其在水和有机溶剂中的光解特性和影响因素。结果表明:烯啶虫胺在酸性和中性条件下不易水解,而在碱性条件下水解较快。烯啶虫胺的水解速率随温度升高而增加,平均温度效应系数为2.34。烯啶虫胺水解反应的活化能和活化焓与温度之间无明显相关性,而活化熵与温度表现出较好的相关性。在不同光源照射下,烯啶虫胺在水溶液中的光解速率有显著的差异,在高压汞灯、自然光和氙灯下的光解半衰期分别为42.3 s、6.9 min和55 min;烯啶虫胺在甲醇中的光解速率大于丙酮中的光解速率;烯啶虫胺的光解速率随初始质量浓度的升高而减慢;pH值对烯啶虫胺的光解影响较小。研究结果为烯啶虫胺的环境风险评价提供了科学依据。  相似文献   

2.
哒嗪硫磷水解与土壤降解研究   总被引:1,自引:0,他引:1  
赵锋  罗婧  王鸣华 《生态环境》2012,21(4):780-785
采用室内模拟方法,研究了哒嗪硫磷在东北黑土、江西红壤和南京黄棕壤3种不同类型土壤中的降解特性及pH、温度和表面活性剂(SDS)浓度对水解的影响。结果表明,哒嗪硫磷水解速率随pH值与温度的升高而显著加快,在15℃、pH 5缓冲溶液中水解半衰期为216.56 d,在35℃、pH 9缓冲溶液中半衰期为3.47 d,平均温度效应系数为2.98。SDS能显著抑制哒嗪硫磷水解,且随着浓度的增大抑制作用增强。哒嗪硫磷在3种土壤中的降解速率依次为南京黄棕壤〉东北黑土〉江西红壤,半衰期分别为10.27、78.75、105.00 d,降解速率随土壤pH值的增大而增大。灭菌处理下,哒嗪硫磷在3种土壤中半衰期显著延长,其中在南京黄棕壤中半衰期延长近10倍,哒嗪硫磷在土壤中降解主要为微生物降解。  相似文献   

3.
为明确环氟菌胺的水解动力学规律,采用室内模拟试验方法,探究了温度、p H值、表面活性剂和不同种类水体对环氟菌胺水解的影响。结果表明:随着温度的升高,环氟菌胺的水解速率加快;环氟菌胺在碱性条件下降解最快;十二烷基磺酸钠(sodium dodecyl sulfonate,SDS)抑制环氟菌胺的水解;腐植酸的浓度低于1 mg·L-1时促进环氟菌胺的水解,浓度高于1 mg·L-1时抑制环氟菌胺的水解;环氟菌胺在不同水体中的水解速率顺序为:海水>江水>河水,环氟菌胺在自然条件下的降解速率显著高于室内模拟条件。  相似文献   

4.
三唑酮在不同pH值和温度条件下水解动力学的测定结果表明:三唑酮在酸性条件下比较稳定,不易水解,但随体系pH值的升高,水解速度加快。温度升高有利于三唑酮的水解反应,酸性条件下水解活化能最大,温度升高对反应速率的影响最大。  相似文献   

5.
甲酰氨基嘧磺隆在模拟环境中的降解特性   总被引:1,自引:0,他引:1  
甲酰氨基嘧磺隆是一种新型磺酰脲类除草剂,其在环境中的归趋备受关注.采用室内模拟试验方法,研究了甲酰氨基嘧磺隆在不同土壤中的降解性、水解和光解特性.结果表明,甲酰氨基嘧磺隆在光照强度4000 lx,紫外强度25μW·cm~(-2)的人工光源氙灯条件下,甲酰氨基嘧磺隆的光解半衰期为1.72 h,易光解.25℃时,pH4、pH7和pH9条件下水解半衰期分别为4.17、91.2、97.6 d,50℃时的水解半衰期分别为1 d、4.75 d和14.5 d,温度和p H值对水解速率具有较大影响.甲酰氨基嘧磺隆在江西红壤、太湖水稻土和东北黑土中的降解半衰期分别为10.8、16.6、31.5 d,该药在酸性土壤中降解较快,影响其在土壤中降解速率的主要因素为土壤pH值.  相似文献   

6.
柳葛贤  吕功煊 《环境化学》2007,26(5):626-629
研究了过渡金属硝酸盐及Al2O3为载体担载催化剂在罗丹明B臭氧氧化过程中的催化作用,考察了温度、pH值以及催化剂浓度等因素对反应的影响.结果表明,过渡金属离子可显著地提高罗丹明B的脱色速率,而担载型过渡金属氧化物催化剂活性较低.较低的pH值和反应温度有利于罗丹明B的催化臭氧化.罗丹明B溶液经过催化臭氧氧化后COD去除率可提高24%.  相似文献   

7.
以方阵法筛选甲萘威ELISA的抗原和抗体浓度 ,并建立了甲萘威的标准抑制曲线 ;以直接竞争性ELISA为基础 ,考察了单克隆抗体的特异性和ELISA法的各种影响因素 ;在黄瓜样品中添加定量甲萘威 ,用ELISA法和HPLC法检测其中甲萘威的含量 .结果显示 ,ELISA法的最低检测限为 4 .1ng/mL ,单克隆抗体对甲萘威的特异性较强 ;甲萘威的ELISA法受分析液中离子强度、pH值、有机溶剂和样品基质浓度的影响 ;ELISA回收率在 89.4 %~ 10 3.2 %之间 ,变异系数为 7.8%~ 10 .7% ;ELISA和HPLC两种方法分析结果无显著性差异 (P >0 .0 5 ) .本研究成功建立了甲萘威的直接竞争ELISA法 ,并将该方法初步应用于黄瓜样品中甲萘威的快速检测 .图 5表 2参 6  相似文献   

8.
三唑酮的酸性、中性和碱性水解动力学研究   总被引:4,自引:1,他引:4  
三唑酮在不同pH值和温度条件下水解动力学的测定结果表明:三唑酮在酸性条件下比较稳定,不易水解,但随体系pH值的升高,水解速度加快。温度升高有利于三唑酮的水解反应,酸性条件下水解活化能最大,温度升高对反应速率的影响最大。  相似文献   

9.
双氯芬酸在水环境中光降解的初步研究   总被引:3,自引:0,他引:3  
考察了在模拟太阳光照射下,双氯芬酸初始浓度、pH值、光强、温度、丙酮和双氧水对双氯芬酸光解的影响,并通过淬灭实验初步探讨了双氯芬酸光解.结果表明,双氯芬酸的光降解过程符合准一级动力学方程.光解速率随着双氯芬酸初始浓度的降低、光强的增强以及温度的升高而增大.当pH值从3变化到5时,反应速率常数变大;pH值从5变到8时,反应速率常数变小,再继续增大pH值,反应速率常数增大.水环境中存在的双氧水和丙酮对双氯芬酸的光解具有促进作用.最后,通过淬灭实验表明双氯芬酸的光解过程包括直接光解以及通过活性氧物种进行的自敏化光解.  相似文献   

10.
陈茜茜  陈秋兰  宋伟  陈猛  袁东星 《环境化学》2014,(12):2136-2143
在亚热带冬、夏两季室外自然光照和温度条件下,研究了环境浓度下乙草胺、丁草胺和异丙甲草胺在河水和海水基底中的非生物降解(水解+光解)行为,并结合室内实验研究了非生物降解的影响因素.室外实验结果表明,冬季(气温12.30—26.98℃,平均17.47℃)乙草胺、丁草胺和异丙甲草胺在河水中的非生物降解半衰期(t1/2)为64—131 d、水解t1/2为105—346 d、光解t1/2为159—410 d,海水中非生物降解t1/2为89—193 d、水解t1/2为77—277 d、光解t1/2为417—630 d;夏季(气温20.77—30.37℃,平均27.22℃)3种目标农药在河水中非生物降解t1/2为4—20 d、水解t1/2为7—54 d、光解t1/2为7—32 d,海水中非生物降解t1/2为10—50 d、水解t1/2为23—67 d、光解t1/2为17—192 d.目标农药在海水中的残留持久性远高于河水;超纯水条件下,光解在目标农药的非生物降解中占主导地位;河水中的光解速率快于海水.室内实验发现,硝酸盐促进了3种目标农药的水解,同时对乙草胺和丁草胺的光解也起到促进作用;p H升高促进了异丙甲草胺的水解和光解速率,但是抑制了丁草胺的水解和乙草胺、丁草胺的光解;腐殖质添加浓度为10 mg·L-1和20 mg·L-1时促进了3种目标农药的水解,但在浓度达30 mg·L-1时则抑制了乙草胺的水解及异丙甲草胺的光解.总体而言,3种目标农药在实际水环境中的降解半衰期均较长,其降解机理和毒性效应值得进一步研究.  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

13.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

14.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

15.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

16.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

17.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

18.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

19.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

20.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

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